Patent GB-600957-A (GB)
Title: Improvements relating to liquid flow meters
IPC: G01F15/00
Filed: 1945-08-24
Abstract: 600,957. Fluid-actuated valves. TECALEMIT, Ltd., and LE CLAIR, C. C. S. Aug. 24, 1945, No. 21809. [Class 135] [Also in Group XVIII] In a liquid flow-meter of the type comprising counter mechanism including a number of counter members or drums which can be preset to determine the quantity of liquid to be delivered by the meter, control of the meter valve is effected by mechanism comprising a single detent device controlled by the counter drum mechanism, acting, in its operative position, to hold the meter valve open until a predetermined portion of the total liquid to be delivered has passed, when it is released and the valve is allowed to close gradually under the control of kinematic chain mechanism connected with the meter mechanism, as the balance of the total quantity of liquid to be delivered passes through the meter, the arrangement being such that by varying the length of one, or some, of the members of the kinematic chain, the rate of closing of the valve relative to the meter motion may be varied. The presetting counter, mounted within a box 5 on the meter 1, comprises a units drum 6, a tens drum 7 and a hundreds drum 8 provided with presetting plungers 9, 10, 11 engaging teeth 13 on the drums. Followers. 16, 17, 18 having rollers 16A., 17A, 18A coacting with semicircular notches 16B, 17B, 18B on the drums are fixed to a shaft 15 whereby the shaft can rotate anticlockwise as seen in Fig. 1, only when all the drums indicate zero and the notches 16B, 17B, 18B lie opposite the rollers 16A, 17A, 18A. The meter valve 19, having an actuating stem 21, is opened by raising a lever 20 fixed to a spindle 34, the valve being held in the open position by a spring-pressed detent 25 fixed to a spindle 26. A spindle 28, driven in an anti-clockwise direction by the meter mechanism, has fixed thereto a disc 32, and also carries a loosely mounted arm 33 connected by a link 37 with an arm 36 fixed to the spindle 34. A spring- loaded pawl 40 mounted on a pin 39 permits the arm 33 to move clockwise relative to the disc 32, but prevents relative movement in the opposite direction. Thus, when the lever 20 is raised to open the valve, the arm 33 is permitted to rotate about the spindle 28, and when the valve is open, the disc 32 may rotate as the liquid flows through the meter. When sufficient liquid has been delivered to return the drums 6, 7, 8 to zero, the followers 16, 17, 18 drop into their respective notches, under the influence of spring means (not shown), and cause the withdrawal of the detent 25 from the lever 20 by means of an arm 42, link 44 and arm 46 attached to the spindle 26, a pin-and-slot connection 47, 48 being provided to allow movement of the detent when opening the valve. When the detent is withdrawn, the valve tends to close, but its rate of closing is limited by the speed of rotation of the disc 32, since the pawl 40 prevents the arm 33 from overrunning the disc. When the counter drums 6, 7, 8 indicate zero, a quantity of liquid has still to be delivered, corresponding to one revolution of a fractional drum 14, not used as an indicator, closure of the valve taking place on the completion of this revolution. The rate of closing of the valve may be varied by alteration of the lengths of the arms 33, 36, and of the link 37, and in one arrangement, the valve is caused to approach gradually towards the closed position until the exact quantity of liquid has been delivered, when the disc 32 loses control as a dead-centre position of the arm 36 with respect to the link 37 is reached, and the valve shuts rapidly.